1. Field of the Invention
The present invention relates to a wrench, and more particularly to a wrench which can be adapted to be used in narrow working spaces, and a wrench which can be driven by a tool for operating.
2. Description of the Prior Art
Conventional wrenches are disclosed in patents such as U.S. Pat. Nos. 5,540,122, 4,867,016, 4,491,042 and US20040093990. The wrenches in the patent mentioned above use various driving structures to enable those wrenches of being driven by a tool to operate in narrow working spaces. In other words, those wrenches use a single driving structure to have an end of one working member drive an end of another working member.
The wrenches described above are straight and flat-shaped. However, speaking of operating in narrow working spaces, it's not easy for users to hold the straight and flat-shaped wrench. Thus, users would hold the wrench unstably with shaking, and it's also difficult to focus power on one of the working members in order to drive another working member rotating. As a result, users need more time and attention to finish a work. Moreover, it is also possible that the wrench would fall into the narrow working space during an operation period because of holding unstably.
Therefore, a wrench with a special design could improve the problems mentioned above. For instance, a wrench with stair-shaped design could be an option. If the wrench is made with stair-shape design, and those two working members still have to be driven by the driving structure to keep effects of linking rotation. An outer shell of the wrench with stair-shaped design needs to be enlarged so as to contain those two working members and the driving structure. On the other hand, once the outer shell is enlarged, the wrench would not be able to enter the narrow working space, and advantages before reforming are nonsense as well. The application of the stair-shaped wrenches would be limited.
Furthermore, because the wrenches mentioned above have only a single driving structure, those wrenches can only be equipped with two working members at two ends of wrenches along a longitude direction of those wrenches. When working in some narrow working spaces, penetrating holes of both two ends of the shell, protruded by a working member, are obstructed due to an operation angle, so users can not drive any working member through any penetrating hole on both two ends of the shell. That means applications of the wrenches are limited by working environments.
With concerns about problems described above, it is necessary to design a wrench which can be held stably with minimized size, and be adapted to be used in various narrow spaces of working environments.